1. Field of the Invention
This invention relates to a discharged paper receiver unit for an image recording apparatus such as a copier, printer or the like, and more particularly to a discharged paper receiver unit on which a plurality of papers automatically discharged from such an image recording apparatus continuously one by one are stacked with their edges lined up.
2. Description of the Related Art
There have been known various image recording apparatuses in which a plurality of papers are continuously discharged one by one onto a discharged paper receiver unit.
Conventional discharged paper receiver units generally comprise a tray on which papers are stacked, an end fence which is erected from the tray so that the papers discharged from the image recording apparatuses impact against the end fence, and a pair of side fences which line up the side edges (the edges parallel to the direction of discharge of the papers) of the papers. The end fence is slidable back and forth in the direction of discharge of the papers according to the length (the size of the papers as measured in the direction of discharge of the papers) of the papers to be discharged from the image recording apparatus. The side fences are slidable toward and away from each other in the direction transverse to the direction of discharge of the papers according to the width of the papers to be discharged. The end fence and the side fences are collapsible, and when the image recording apparatus is not used, the discharged paper receiver unit is housed in a cabinet on the image recording apparatus with the fences collapsed.
In the conventional discharged paper receiver units, the end fence functions as both a stopper member which stops the papers discharged from the image recording apparatus and an end lining up member which lines up the leading ends of the papers, thereby bringing the papers in alignment with each other in the longitudinal direction of the papers (in the direction of discharge of the papers).
Generally the end face has been formed of synthetic resin such as ABS resin, PS resin or PC resin. Accordingly a large sound is generated each time the paper impacts against the end fence.
There has been made an attempt to suppress the impact sound by providing a cushioning member such as of sponge on the end fence in a position where the papers impact against the end fence.
However when the sponge is exposed, the leading ends of the papers are apt to be caught by the rough surface of the sponge so that the papers are hung from the sponge, which adversely affects lining up the leading ends of the papers, though the impact sounds can be well suppressed. To the contrast, when the surface of the sponge is covered, for instance, with resin film to provide a smooth surface, the cushioning effect deteriorates and the impact sound cannot be sufficiently suppressed though the lining up the leading ends of papers can be well performed.
In Japanese Unexamined Patent Publication No. 8(1996)-20468, there is disclosed a mechanism for suppressing the impact sound by erecting a thin plate member formed of a resilient material in front of the end fence. The thin plate member is deflected by its own weight toward the paper discharge port of the image recording apparatus and when the paper impacts against the thin plate member, kinetic energy of the paper is absorbed by the thin plate member and the impact sound is suppressed. However, this approach is disadvantageous in that deflection toward the paper discharge port of the thin plate member adversely affects lining up the leading ends of the papers and, at the same time, as the number of papers stacked on the tray increases and the weight of the stack of papers acting on the thin plate material increases, cushioning effect of the thin plate member deteriorates and the impact sound gradually becomes larger.
In view of the foregoing observations and description, the primary object of the present invention is to provide a discharged paper receiver unit which can suppress the impact sound generated upon stopping the discharged paper and, at the same time, can well line up the ends of the papers.
The discharged paper receiver unit in accordance with the present invention is for receiving papers discharged from an image recording apparatus such as a copier, printer or the like and comprises
a bottom plate on which papers discharged from the image recording apparatus are stacked and which is positioned with its one end held lower than the other at least when the discharged paper receiver unit is set in its operative position,
a stopper member having a cushioning portion positioned so that the leading end of each paper as discharged from the image recording apparatus directly impacts against the cushioning portion and the paper falls onto the bottom plate, and
an end lining-up member which is provided near the end of the bottom plate which is held lower than the other when the discharged paper receiver unit is in its operative position, is positioned so that the leading end of each paper as discharged from the image recording apparatus cannot directly impact against the end lining-up member before impacting cushioning portion, and is provided with a lining-up surface which is erected from the bottom plate and against which one end of the paper is brought into abutment after the leading end of the paper impacts against the cushioning portion.
In the discharged paper receiver unit of the present invention, the cushioning portion of the stopper member stops the paper discharged from the image recording apparatus and absorbs kinetic energy of the discharged paper by rebounding the discharged paper, whereby the impact sound is suppressed. Since the end lining-up member lines up the ends of the papers and the cushioning portion plays no part in lining up the ends of the papers, the surface of the cushioning portion need not be smooth. Accordingly, the cushioning portion may be formed of a cushioning material such as sponge rubber or sponge resin without any cover which can increase the impact sound. The cushioning portion may extend either from the surface of the bottom plate to an area including a height where the leading end of the discharged paper is expected to pass or only over an area including a height where the leading end of the discharged paper is expected to pass. The height where the leading end of the discharged paper is expected to pass varies according to the size of the paper, the thickness of the paper, the speed at which the paper is discharged and the like, and can be determined, for instance, empirically. It is preferred that the height of the cushioning portion is adjustable.
Further since kinetic energy of the paper to be absorbed by the cushioning portion varies according to the size of the paper, the thickness of the paper, the speed at which the paper is discharged and the like, it is preferred that the material of the cushioning portion can be changed. This can be realized by changing the stopper member together with the cushioning portion or by removably mounting the cushioning portion on the stopper member and changing only the cushioning portion.
The paper is generally discharged in a curled state with its side edges directed upward in order to facilitate discharge of the paper. In such a case, when the leading end of the paper abuts against the cushioning portion over the entire length of the leading end, a paper spreading sound is generated when the paper spreads. When the cushioning portion is narrower than the width of the leading end of the paper to be discharged from the image recording apparatus and is positioned so that the leading end of the paper impacts against the cushioning portion only at a middle portion thereof, impact energy is released in a manner such that the impact energy propagates outward from the middle portion of the paper, and a part of the impact energy can be absorbed and generation of the paper spreading sound is prevented.
The end lining-up member is disposed near the end of the bottom plate which is held lower than the other end, and the paper rebound by the cushioning portion slides along the inclined surface of the bottom plate and is stopped by the end lining-up member with its one end abutting against the lining-up surface of the end lining-up member, whereby the ends of the papers are lined up. For this purpose, it is preferred that the lining-up surface be smooth and may be formed of synthetic resin such as ABS resin, PS resin, PC resin or the like which has been used for the conventional end fence. Though the bottom plate may be inclined either so that the upstream end thereof (the end nearer to the image recording apparatus) is lower than the downstream end thereof or so that the downstream end is lower than the upstream end, it is preferred that the bottom plate be inclined in the latter manner.
The stopper member and the end lining-up member may be formed either integrally or separately from each other.
It is preferred that the stopper member and the end lining-up member be movable back and forth in the paper discharge direction in which the papers are discharged from the image recording apparatus so that the position of the cushioning portion and the lining-up surface can be adjusted according to the size of the paper.
It is further preferred that the stopper member and the end lining-up member be movable back and forth in the paper discharge direction independently of each other.
Further, in the discharged paper receiver unit of this embodiment, since the weight of the stack of the papers does not act on the stopper member, the cushioning performance of the stopper member (the cushioning portion) is kept unchanged even if the number of papers in the stack increases and the weight of the stack is increased.